HomeMy WebLinkAboutMemo - Mail Packet - 9/21/2021 - Memorandum From Matt Parker, Amy Resseguie And Tyler Marr Re: West Nile Virus - Weekly Update - End Of Season Data 1745 Hoffman Mill Road
PO Box 580, Fort Collins, CO 80522-0580
MEMORANDUM
Date: September 16, 2021
To: Mayor and City Councilmembers
From: Matt Parker, Sr. Supervisor, Natural Areas
Amy Resseguie, Sr. Specialist, Communications & Public Involvement
Tyler Marr, Assistant City Manager
Through: Kelly DiMartino, Interim City Manager
Seve Ghose, Director, Community Services
Mike Calhoon, Director, Parks
Zoe Shark, Interim Director, Natural Areas
Subject: West Nile virus (WNV) – Weekly Update – End of Data Season
Summary:
Contractors completed a third and final WNV adult mosquito treatment on Sunday, September
12 to mitigate WNV risk in a 6-trap area in the southeast portion of the city. Data indicated a
vector index value of 0.79 in the area east of College Ave., south of Horsetooth Rd., west of
Ziegler Rd., and north of Kechter extending back to College Ave. The Larimer County Health
Department (LCDH) recommended this treatment area based on the vector index value and
considering predicted warm temperatures with higher-than-normal overnight low temperatures
extending the traditional WNV season.
This is the final dataset for 2021, although conditions of risk are likely to continue for the next
few weeks. As the detection of human WNV cases lags the peak infection date, most years
bring additional human case reports in the coming weeks.
Current Vector Index:
Week No: 36 Vector Index
Threshold:
Previous Week Vector
Index:
Current Vector
Index:
FC – Zone NW NA 0.07 0.03
FC – Zone NE NA 0.09 0.00
FC – Zone SE NA 0.32 0.18
FC – Zone SW NA 0.05 0.05
FC – Citywide NA 0.19 0.10
Floating Zone 0.75 0.79 0.64
Review of 2021 WNV Season: Exceptionally high abundance of Culex species mosquitoes
during the earliest summer weeks proved to drive the WNV risk throughout the season. Trap
data showed abundance values 2x the historic average during many key weeks leading up to
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City of Fort Collins
the peak weeks, particularly in the northeast and southeast quadrants. As WNV inevitably
amplified, the abundance values drove the vector index values.
Technical Advisory Committee (TAC): The WNV TAC will convene to review the 2021 season
while developing recommendations for improvement for the upcoming seasons. Likely
discussion topics will include:
How to overcome potential budget reductions
How to expand the trapping network to cover recent City expansion
How to address climate change driving the expansion of mosquito breeding seasons
Explore recent WNV research conducted by CSU’s OneHealth Institute
Meeting dates are set for January 19, February 16, March 16, and April 20 of 2022.
2022 WNV Program Outlook:
Potential budget reductions will lead to decreased trapping and testing during the 2022 season.
Staff is anticipating a need to add additional trapping locations to provide better data coverage
while exploring ways to reduce costs, which will likely come in the form of fewer trap-weeks.
Public outreach will remain limited to low-cost opportunities with a focus on driving people to
sign up for notification via Larimer Emergency Telephone Authority.
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